This proposal requests partial support for a 2.0 Tesla real time magnetic resonance (MR) imaging system. The hospital and NMR program will provide the additional funding and long-term support for this dedicated research instrument. As part of the MGH-NMR research program, this system will be a resource to the community of PHS-supported biomedical researchers at the MGH managed by the Internal Advisory Committee as outlined by the Division of Research Resources in the program announcement. The scope of the MGH-NMR program, which is largely funded through PHS grants, has expanded to include the study of magnetic susceptibility effects induced by the introduction of high magnetic moment contrast agents such as Gd-DTPA into the intravascular space. Transient susceptibility-induced spin echo and gradient echo signa attenuation has been demonstrated in preliminary studies to correlate with blood flow. Optimization of these experiments, especially for cardiac studies, requires and MR imaging system with high temporal resolution (1/30th sec/image) that does not presently exist at the MGH. The proposed real time system also eliminates artifacts from physiologic motions, acquires chemical shift resolution images, and provides increased signal-to-noise for MR angiographic studies. The only available system is located in a facility ten miles from the MGH, offers limited access to MGH investigators, and is not licensed for important correlative studies such as use of radioactive microspheres. While this system has been made available, there is insufficient time and resources to perform adequately the appropriate experiments. The group of biomedical research projects this instrument will support has a broad range of interests. The projects include MR studies of myocardial perfusion, real-time cardiac functional imaging, MR perfusion imaging in brain, chemical shift imaging in bone marrow disease, functional MR imaging of liver metastases with paramagnetic contrast agents, and MR angiography. It is anticipated that the level of scientific activities of PHS- supported researchers will be significantly enhanced by the presence of this research instrument at the MGH.